Question

Describe three different mechanisms or devices for selecting specific wavelengths for use in spectrophotometers.

3.​What are the ideal characteristics of the cuvets used in visible/UV spectrophotometers?

ans as soon as possible .

Define reflection, refraction and light scattering.

10.​Show graphically the relationship between concentration and % transmittance

Answer 1

1) To select specific wavelength solution of different concentration are made and their absorbance is recorded on spectrophotometer, absorbance of one dilute solution is observed on each wavelength and the wavelength at which absorbance is maximum is selected as lembda max.

3)Characteristics of cuvets:

It should not absorb in range of UV and visible. And should not react with compound.

Reflection:it is change in direction of wavefront at an interface between two different media so that the wavefront return into the medium from which it originated.

Refraction: it is the change In direction of propagation of any wave as a result of its travelling at different speeds at different points along the wave front

Light scattering: it is a general physical process where some forms of radiation such as light are forced to deviate from a straight trajectory by one or More Paths due to localized non uniformities in the medium through which they pass.

10)relationship between conc and %transmittance:

As absorbance is directly proportional to conc and inverly proportional to transmittance so transmittance decrease with inc conc as shown